Metal-clad cables having an interlocked metal sheath potentially provide a low impedance and reliable ground path in order to function as an equipment grounding conductor. Once type of such cable described in U.S. Pat. No. 6,486,395, assigned to the assignee of the present invention, contains a conductor assembly having at least two electrically insulated conductors cabled together longitudinally into a twisted bundle and enclosed within a binder/cover. A bare grounding conductor is cabled externally over the binder/cover, preferably within a trough/interstice formed between the insulated conductors. The metal sheath is helically applied to form an interlocked armor sheath around the conductor assembly, and the bare grounding conductor is adapted to contact the sheath to provide the low impedance ground path.
This design provides significant advantages over other metal clad cables not so constructed. In order to maximize its utility and lowest impedance ground path, it is important that adequate contact be maintained between the bare grounding conductor and the interior surface of the metal sheath. This is particularly challenging due to differing wire gauges that may occur between the insulated conductors and the bare grounding conductor. For example, in the event the insulated conductors comprise a low wire gauge (e.g., large diameters) forming a large interstice to receive a bare grounding conductor with a high wire gauge (e.g., a smaller diameter), the desired maximum contact between the bare grounding conductor and the metal sheath may not be achieved due to the bare grounding conductor resting too far within the interstice. One solution is to provide fillers to at least partially fill an interstice and “lift” the bare grounding conductor from within the interstice; however, providing such fillers can, among other things, be costly, labor intensive and unnecessarily increase the overall weight and/or decrease the overall flexibility of the metal-clad cable.